Caltha palustris vs swamp plant

Caltha palustris and swamp plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
Caltha palustris	Yes	No	No	No
swamp plant	Yes	No	No	No

As nouns, swamp plant is a hypernym of Caltha palustris; that is, swamp plant is a word with a broader meaning than Caltha palustris:

Caltha palustris: swamp plant of Europe and North America having bright yellow flowers resembling buttercups
swamp plant: a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath

Other hypernyms of Caltha palustris include bog plant, marsh plant.

Caltha palustris (noun)	swamp plant (noun)
swamp plant of Europe and North America having bright yellow flowers resembling buttercups	a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath